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High alcohol intake link to poorer female fertility

Low to moderate drinking appears not to damage fertility

Adrian O'Dowd

Thursday, 01 September 2016

Women who drink 14 or more servings of alcohol per week appear to have slightly reduced fertility, according to a study* published today in The BMJ.

However, low to moderate intake of alcohol – described as one to seven servings per week – seems to have no effect on women’s fertility, regardless of the type of alcohol consumed, but researchers still recommend couples abstain from alcohol during their fertile window until a pregnancy is ruled out.

In developed countries, as many as 24% of couples experience infertility, defined as time to pregnancy of 12 months or more.

Official guidelines in several countries, including the UK, USA and Denmark, recommend that women trying to become pregnant should abstain from alcohol consumption, but the extent to which alcohol intake affects female fertility is unclear.

A group of researchers led by Ellen Mikkelsen of the Department of Clinical Epidemiology, Aarhus University Hospital, Denmark, therefore, carried out a large study to examine the association between pre-conception alcohol consumption and time to pregnancy.

The study included data on 6,120 female Danish residents, aged 21-45 years, who were all in a stable relationship with a male partner, trying to conceive and not receiving fertility treatment, between June 2007 and January 2016.

The study assessed overall alcohol consumption as well as intake of specific types of alcohol, including beer, wine, and spirits.

Alcohol consumption was self reported as beer (330 ml bottles), red or white wine (120 ml glasses), dessert wine (50 ml glasses), and spirits (20 ml), and was categorised in standard servings per week (none, 1-3, 4-7, 8-13, and 14/more).

Each female participant completed bimonthly questionnaires for 12 months, or until she became pregnant, on alcohol use, pregnancy status, menstrual cycles, frequency of intercourse, and smoking. 

During the study period, 4,210 (69%) participants became pregnant and the average alcohol intake was 2 servings per week.

Results showed that in women who drank 14 or more servings of alcohol per week, there were 37 pregnancies in 307 cycles, compared with 1,381 pregnancies in 8,054 cycles in women who did not drink.

The authors cautioned that although the sample size was large, only 1.2% of women drank more than 14 servings of alcohol a week, so the estimate for this high level of exposure was imprecise.

This is an observational study, so no firm conclusions can be made about cause and effect.

Nevertheless, consumption of less than 14 servings of alcohol per week seemed to have no discernible effect on fertility, but the authors still advised couples to abstain from alcohol during their fertile window until pregnancy was ruled out, because the foetus may be particularly vulnerable to alcohol during the first few weeks after conception.

In a linked editorial,** Annie Britton from the Department of Epidemiology and Public Health at University College London, said: “Total abstinence may not be necessary to maximise conception rates.

“If alcohol is consumed moderately, it seems that this may not affect fertility. However, it would be wise to avoid binge drinking, both for the potential disruption to menstrual cycles and also for the potential harm to a baby during early pregnancy.”


* Mikkelsen EM, et al. Alcohol consumption and fecundability: prospective Danish cohort study. BMJ 2016;354:i4262. doi: 10.1136/bmj.i4262

** Britton A. Alcohol consumption for women trying to conceive. BMJ 2016;354:i4540. doi: 10.1136/bmj.i4540

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